Mt. Vesuvius 1944 eruption light show -- Static electricity?

[difalcojr]

TL;DR

photo of Vesuvius volcanic eruption

The caption says this volcanic 'light show' was caused from "an accumulation of static electricity". If that is so, I do not know the physical reason for that at all. Hopefully, someone can enlighten the ignorant.

If it is something other than that, possibly, my guess would be that ingredients in the air have been agglomerated somehow into gunpowder, black powder. Photo reminds me more of 'sparklers' on the 4th of July. Needed ingredients would be sulfur, and potassium and nitrogen gases for the potassium nitrate. Those would be available in the magma, I think. Last, charcoal from all the organic material that would be in the air as ashes, the lava burning a lot of ground cover growth on the mountain. All the ingredients, I think, and plenty of heat to ignite the mix.

 

[Baluncore]

Hopefully, someone can enlighten the ignorant.

Science says that it is particles of ice, or ash, being rubbed together in the clouds, that causes friction electrification, then lightning. That has never been demonstrated experimentally, so there are many alternative mechanisms proposed.
https://en.wikipedia.org/wiki/Volcanic_lightning

My preferred alternative model is that the rising thermal plume of ions, is separated by polarity in the Earth's magnetic field. That is an MHD process, that builds up a potential voltage difference across the vertical flow. There is then voltage breakdown, and secondary ionisation, around and through the plume, that we call volcanic lightning.
https://en.wikipedia.org/wiki/Magnetohydrodynamic_generator

The first physics lessons about charges moving in magnetic fields, is that charged particles move in circular or helical paths. But that is only in a vacuum, where the particle does not encounter collisions that exchange momentum with other particles. In the lower atmosphere, a more realistic model is that of an MHD generator.

Let the controversy continue.

 

[difalcojr]

I like your alternative model for an electrical explanation.
To me the photo had reminded me of a pyrotechnic display, so I had thought it just might be caused by a chemical reaction only. Wanted to float the idea out there. Didn't know there was a controversy!
Your posts on other threads are super informative, and I've learned a lot about electrical matters from them, thanks. Was hoping you would answer on this topic too.

 

[Klystron]

While electrical effects cause volcanic lightning displays, your question about chemical reactions from ejaculate materials intrigues. Formation and eruption of magma and 'lava bombs' certainly produce some spectacular visual displays during active eruption including clouds of dust and pumice extending high in the atmosphere.

While not based on the constituents of gunpowder, the release of gases trapped in molten rock and the pressure difference between underground magma and surface eruptions contributed to the spectacle described in your book. Roman historian Tacitus documents two letters from Pliny who witnessed the 79CE devastating eruption of Vesuvius.

A massive black cloud glistering with lighting obscured the early-morning light, a scene Pliny describes as sheet lightning.

 

[Baluncore]

Here is an earlier thread that includes the topic of volcanic lightning.
https://www.physicsforums.com/threads/did-the-1883-krakatoa-explosion-leave-ships-in-peril.879869/

 

[pinball1970]

I like your alternative model for an electrical explanation.
To me the photo had reminded me of a pyrotechnic display, so I had thought it just might be caused by a chemical reaction only. Wanted to float the idea out there. Didn't know there was a controversy!
Your posts on other threads are super informative, and I've learned a lot about electrical matters from them, thanks. Was hoping you would answer on this topic too.

The latest one in Indonesia did similar

https://www.theguardian.com/world/v...pts-forcing-nearby-villages-to-evacuate-video

 

[hutchphd]

Wanted to float the idea out there.

Most of the really sperkly bits in fireworks are metallic inclusions specifically added create that effect: small inclusions of (powdered/granulated) Al and Mg will create brightburning sparkles. I think "sparklers" are similar to thermite powder (?true?) which is Al and FeO_x

 

[difalcojr]

Good info. Al and Mg in the coating over what is essentially a black powder fuse-on-a-stick, the hand-held sparkler. Don't know anything about thermite but now know that it is similar, thanks. It was the 'crackling' sound mentioned in the OP caption that reminded me of sparklers.

Looked at the Krakatoa volcano thread cited above and found a whole lot of material linked there to go over, time willing, on lightning causes. And a very exciting narrative!

To me now seems volcanic lightning and eruption effects are sometimes caused by normal lighting causes only, but may include electro-chemical and chemical, explosive reactions too. I'll check further on them.

On other explosive ingredients in the mix, besides those of black powder or of thermite, there would be ammonium nitrate (Prell in industry, small, pebble-size agglomerates). Ammonia and sulfuric acid smells are noted as strong smells in the accounts given by witnesses.

Mammoth Mountain, an ancient volcano in California, is a huge ski resort, at almost 2500m (8000 ft) elevation. It has a huge, rising magma pot under it and farly close to the surface. Nearby are previous, geologic, super eruptions, the Long Valley caldera and Mono Lake. No volcanic activity, though.

 

[hutchphd]

No volcanic activity, though.

Yet?

 

[difalcojr]

USGS monitors it daily. There was high anxiety some years ago about the rising rate of the caldera. 1980, '81 had some big earthquakes. Fears subsided now. No activity on the mountain itself, but the Long Valley caldera itself has active dangers that surface.

High carbon dioxide concentrations vent, continuously in small amounts in certain areas, but sometimes in sudden, larger volume ventings that have been lethal in the past. You have to watch where you camp if you are camping out. https://pubs.usgs.gov/dds/dds-81/In...nia,,mountain and can pose a threat to humans.

There are also lots of hot springs all over the area. Hot Creek is popular with skiers to soak their tired bones in hot waters that bubble up through the sandy bottom of the creek. Gets very hot in spots along that creek.
https://www.usgs.gov/volcanoes/long-valley-caldera
https://www.usgs.gov/volcanoes/mammoth-mountain

 

[difalcojr]

Yet?

Boy, was I wrong! There was fumarole venting on the mountain itself too! From https://en.wikipedia.org/wiki/Mammoth_Mountain

In April 2006, three members of the Mammoth Mountain Ski Area ski patrol died while on duty when a fumarole caused a snow bridge to collapse under the patrollers.[20] The 2005/2006 winter season delivered significant snow depth of 52 feet (16 m).[21] As the ski patrollers assessed the fumarole for skier safety, the perimeter snow collapsed, dropping the patrollers 21 feet (6.4 m) into the bottom of the fumarole, exposing them to extremely high levels of carbon dioxide.[22] It is unclear if they died as a result of the fall or as a result of the gas.[22]
Also, on ground level around the mountain,
...soil concentrations of CO2 in the tree-kill areas ranged from 20% to 90%. This overabundance of CO2 was found to be the cause of the tree-kills because tree roots need to absorb O2 directly and the high CO2 level reduced available O2. Researchers also determined that Mammoth releases about 1,300 short tons (1,200 t) of CO2 every day.
To sum:
Mammoth Mountain is a 3,369-m (11,053 ft) high lava-dome complex on the southwest topographic rim of Long Valley Caldera. It is considered to represent a magmatic system distinct from Long Valley Caldera and the Mono-Inyo Craters. https://www.usgs.gov/volcanoes/mammoth-mountain

Sorry, I got the OP off track: Went from electrical, to possible electro-chemical, to chemical reaction dangers of volcanic activity. Eastern Sierra Nevada ranges in California have active volcanos.

 

[berkeman]

Yet?

So how did your skiing vacation go?